Date: Tue, 20 Apr 2004 11:53:22 +0300 From: Rumen Telbizov <altares@e-card.bg> To: Kris Kennaway <kris@obsecurity.org> Cc: stable@freebsd.org Subject: Re: HTT and SMP question Message-ID: <20040420085322.GV32493@e-card.bg> In-Reply-To: <20040420081334.GA56291@xor.obsecurity.org> References: <20040419085841.GB64662@freenix.no> <20040419090049.GA51659@chihiro.leafy.idv.tw> <20040419092052.GD64662@freenix.no> <20040419093523.GA34419@xor.obsecurity.org> <20040420073837.GS32493@e-card.bg> <20040420081334.GA56291@xor.obsecurity.org>
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> > Would you please point out some cases when HTT with machdep.hlt_logical_cpus=0 > > causes worse performance than machdep.hlt_logical_cpus=1? > > I am using an HTT Xeon since recently and in my tests it showed that > > machdep.hlt_logical_cpus=0 is better! > > A simple ubench (spawning 2 processes) gives better results in 0 mode! > > My parallel package builds are slower on build machines with HTT. > It's not a magic bullet. > > Kris Hmm ... interesting. My simple/stupid synthetic tests showed just the opposite. Anyway. Unfortunatelly I didn't try to buildworld/kernel with -j2 (say). Shame on me! Would you point to a case where machdep.hlt_logical_cpus=0 does show better performance results? httpd ? Is it not that exactly _parallel processing_ should be faster with HTT than whithout ? Thank you for your reply. Rumen Telbizov
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